A. Field of the Invention
The present invention relates to an apparatus and method for a barrier system which allows the selective shielding of plants from certain things; and in particular, to a barrier which passes a desired amount of plant growth requisites while blocking undesired substances from the plants. In one aspect of the invention, the barrier is used in pollination breeding experiments to control or block pollen without detrimental effect on growth of the plant or seed yield or other undesirable results.
B. Problems in the Art
The development of plant breeding has occurred for many years. The basic concept involves selecting a plant to breed with another plant to produce an offspring with improved or desired characteristics. To be effective, the cross-pollination must be accurate. Desired pollen from the male part of one plant must be collected and emplaced on the female part of the second plant at the proper time without contamination by undesirable pollen. Presently, conventional cross-pollination methodology requires multiple passes through the experimental plot. The first pass looks for female shoots. A worker covers each female shoot, typically with a small sack, to protect it against receiving undesirable pollen. If not covered, it would be exposed to anything. Undesired pollen could be carried by wind, insects, birds, or workers and contaminate the female shoots.
The second pass puts small covers over the male parts of the plants to collect the pollen they generate.
On another pass selected female shoots are pollinated with desired pollen, which requires removing the covers from the male parts of a first plant, carrying the pollen to the female part of the second plant, and physically depositing the same.
This typical cross-pollination process is labor intensive. In requires multiple field passes, coverings, uncoverings and collection. Conventionally, it concentrates on individual parts of individual plants, e.g., small-sized single sacks for small parts of individual plants. The process covers only the part of the plant at risk, uses less material that way, and has lower risk of stunting or otherwise effecting normal growth of the plant because only small, non-leaf parts are covered, and only for a limited amount of time.
However, the magnitude of required labor resources is substantial. It is very labor intensive. Typically, larger seed companies may have on the order of millions of pollinations per year. Therefore, there is room for improvement in the art with respect to the expenditure of human resources. Also, whatever system is employed must be cost effective.
Other issues exist. For example, the quality of pollination must be very high. This raises human error issues for such a labor-intensive task. While wind is a major cause of pollen load in the air, the movement of so many persons through experimental plots increases the risk of contamination by jarring and loosening pollen or carrying pollen in from other plots. Pollen load in the air is increased with movement of people through fields, adding and removing sacks to parts of plants, and not being able to cover all male parts of plants instantaneously. Pollen load increases the risk of contamination.
There are other perhaps more subtle issues. Any foreign addition to a plant may adversely effect its normal growth and development. Even small sacks over female and male parts may diminish the amount of air and moisture to that part of the plant or constraint growth. Also, severe or bad weather may degrade development.
The significant amount of labor involved in artificial pollination creates safety issues. Repetitive stress injury, transportation, long hours and tedium are often side effects of this type of work. This can result in physical injury or accuracy problems.
Low-level contamination is difficult to detect. However, the advent of genetically modified organism (GMO) crops has greatly increased the need to minimize or eliminate contamination.
Therefore, there is need for improvement in the art over typical, historical cross-pollination and insert pollination breeding methods, particularly in light of an increasing number of factors and regulations at play. There is also room for improvement in selfing experiments. It would be advantageous to decrease labor overhead. It would also be advantageous to provide a better barrier between plant and external environment for selected blockage of things. Ideally, control or blockage of all pollen would be desirable.
Various barricades or covers for more than just parts of plants have been tried. For example, cheese-cloth type fabrics have been placed over seedling beds of tobacco plants to shield them from insects and direct sunlight but allow air and water to pass sufficiently so that they can grow to the stage where they could be transplanted to the fields. Another example is canola, which is particularly susceptible to bees carrying in contaminating pollen.
Based on knowledge and belief, these attempts are either limited to use of fabric for a short period of time and for a basic shading function, such as the tobacco seedlings, or to a barrier against insects, but not pollen particles themselves. In both examples, sufficient air and water must pass through the covers to sustain and not detrimentally affect the plants. This, using these conventional materials would require pore sizes larger than most pollen particles.
In some cases where temporary covers are used, the permeability to air, water and light is not high. Sustained covering of the plant could result in adverse effect on growth of the plant or even sustenance of the plant. Also, lack of or reduced breathability or air flow could create super-heated conditions that could burn or stunt the plants. Some covers intentionally thermally insulate a plant. They tend to limit air flow or exchange and have insulating material which increases size and reduces flexibility of the device. They may require some structure to make them self-supporting, and thus, many times have somewhat rigid elements.
There is presently no known adequate solution to these issues.